In recent years, a technique of attaching an input device referred to as a touch panel or a touch sensor to a display surface side of a display and detecting and outputting an input position when input operations are performed by contacting the touch panel with a finger or an input tool such as a touch pen has been known. Since such displays including a touch panel are widely used in portable information terminals such as mobile phones in addition to computers.
One detecting method for detecting contact positions at which a finger or the like has contacted the touch panel is the electrostatic capacitance method. In an electrostatic capacitive touch panel, a plurality of capacitive elements each made up of a pair of electrodes disposed to be opposed to each other with a dielectric layer interposed therebetween, that is, made up of a driving electrode and a detection electrode are provided in a plane of the touch panel. Then, the input positions are detected by utilizing the characteristics that the electrostatic capacitance of capacitive elements changes when performing input operations by contacting the capacitive elements with a finger or an input tool such as a touch pen.
For example, Japanese Patent Application Laid-Open No. 2012-68980 (Patent Document 1) describes a technology for performing scanning by sequentially selecting, in a time-sharing manner, a predetermined plurality number of electrodes to be driven from among a plurality of driving electrodes disposed in parallel to extend in one direction, and by applying touch detection driving signals to the selected electrodes to be driven for detecting an object approaching from the exterior.